It has long been desired to maximize fuel economy, power and driveability in diesel fuel powered vehicles while enhancing acceleration, reducing emissions, and preventing hesitation. While it is known to enhance gasoline powered engine performance by employing dispersants to keep valves and fuel injectors clean in port fuel injection engines, such gasoline dispersants are not necessarily effective fuel injected diesel engines. The reasons for this unpredictability lie in the many differences between the fuel compositions that are suitable for such engines.
Additionally, new engine technologies require more effective additives to keep the engines running smoothly. Additives are required to keep the fuel injectors clean or clean up fouled injectors for spark and compression type engines. Engines are also being designed to run on alternative renewable fuels. Such renewal fuels may include fatty acid esters and other biofuels which are known to cause deposit formation in the fuel supply systems for the engines. Such deposits may reduce or completely bock fuel flow, leading to undesirable engine performance.
Some additives, such as quaternary ammonium salts that have cations and anions bonded through ionic bonding, have been used in fuels but may have reduced solubility in the fuels and may form deposits in the fuels under certain conditions of fuel storage or engine operation. Also, such quaternary ammonium salts may not be effective for use in fuels containing components derived from renewable sources. Accordingly, there continues to be a need for fuel additives that are effective in cleaning up fuel injector or supply systems and maintaining the fuel injectors operating at their peak efficiency.
Also, low sulfur diesel fuels and ultra low sulfur diesel fuels are now common in the marketplace for such engines. A “low sulfur” diesel fuel means a fuel having a sulfur content of 50 ppm by weight or less based on a total weight of the fuel. An “ultra low sulfur” diesel fuel (ULSD) means a fuel having a sulfur content of 15 ppm by weight or less based on a total weight of the fuel. Low sulfur diesel fuels tend to form more deposits in diesel engines than conventional fuels, for example, because of the need for additional friction modifiers and/or corrosion inhibitors in the low sulfur diesel fuels.
In accordance with the disclosure, exemplary embodiments provide a diesel fuel composition for an internal combustion engine comprising, a method for improving performance of fuel injectors, and a method for cleaning fuel injectors for an internal combustion engine. The fuel composition includes a major amount of fuel and a minor effective amount of a reaction product of (i) a hydrocarbyl substituted compound containing at least one tertiary amino group and (ii) at least on halogen substituted C2-C8 carboxylic acid, ester, amide, or salt thereof, wherein the reaction product as made is substantially devoid of free anion species.
Another embodiment of the disclosure provides a method of improving the injector performance of a fuel injected diesel engine. The method includes operating the engine on a fuel composition comprising a major amount of fuel and from about 5 to about 200 ppm by weight based on a total weight of the fuel of a reaction product of (i) a hydrocarbyl substituted compound containing at least one tertiary amino group and (ii) at least one halogen substituted C2-C8 carboxylic acid, ester, amide, or salt thereof, wherein the reaction product as made is substantially devoid of free anion species. The reaction product present in the fuel is effective to improve the injector performance of the engine by at least about 80% when measured according to a CEC F98-08 DW10 test.
A further embodiment of the disclosure provides a method of operating a fuel injected diesel engine. The method includes combusting in the engine a fuel composition comprising a major amount of fuel and from about 5 to about 500 ppm by weight based on a total weight of the fuel of a reaction product of (i) a hydrocarbyl substituted compound containing at least one tertiary amino group and (ii) at least one halogen substituted C2-C8 carboxylic acid, ester, amide, or salt thereof, wherein the reaction product as made is substantially devoid of free anion species.
Another embodiment of the disclosure provides an additive concentrate for a fuel for use in an injected diesel fuel engine. The additive concentrate includes a reaction product of (i) a hydrocarbyl substituted compound containing at least one tertiary amino group and (ii) at least one halogen substituted C2-C8 carboxylic acid, ester, amide, or salt thereof, wherein the reaction product as made is substantially devoid of free anion species; and at least one component selected from the group consisting of diluents, compatibilizers, corrosion inhibitors, cold flow improvers (CFPP additive), pour point depressants, solvents, demulsifiers, lubricity additives, friction modifiers, amine stabilizers, combustion improvers, dispersants, antioxidants, heat stabilizers, conductivity improvers, metal deactivators, marker dyes, organic nitrate ignition accelerators, and cyclomatic manganese tricarbonyl compounds.
An advantage of the fuel additive described herein is that the additive may not only reduce the amount of deposits forming on fuel injectors, but the additive may also be effective to clean up dirty fuel injectors sufficient to provide improved power recovery to the engine.
Additional embodiments and advantages of the disclosure will be set forth in part in the detailed description which follows, and/or can be learned by practice of the disclosure. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure, as claimed.